Per Lee Jenkins of Sports Illustrated, Simmons revealed that James told him the following at the LeBron James Skills Academy four years ago: "You have an opportunity to be better than me. But you can't skip steps. You have to do the work."
Simmons' production this season has been reminiscent of what LeBron did early in his NBA career, as he is averaging 18.7 points, 9.5 rebounds, 7.2 assists and 2.1 steals per game.
Simmons is a mature rookie at 21 after missing all of last season due to injury, and his numbers are arguably more impressive than what LeBron put up in 2003-04.
As a 19-year-old, James averaged 20.9 points, 5.9 assists, 5.5 rebounds and 1.6 steals per contest straight out of high school.
Simmons spent one season at LSU before entering the draft, and it hasn't taken him long to develop into one of the league's most versatile and talented players.
Even so, the 2017-18 Rookie of the Year favorite of course has a long way to go before approaching LeBron's level.
That was apparent Monday when James and the Cavs beat Simmons and the Sixers 113-91. LeBron finished with 30 points, 13 boards and six dimes, while Simmons was limited to 10 points, eight rebounds and two assists before exiting with an ankle injury.
Still, Simmons is a superstar in the making, and he is a big reason why Philadelphia is finally ascending from the NBA's doldrums.
After five straight years without reaching the playoffs, Simmons and the 76ers are fifth in the Eastern Conference at 12-8.